HERE IT COMES: Zack Wheeler threw two shutout innings against the Nationals in his first spring outing for the Mets, but manager Terry Collins still expects the youngster to begin the season at Triple-A Las Vegas.

HERE IT COMES: Zack Wheeler threw two shutout innings against the Nationals in his first spring outing for the Mets, but manager Terry Collins still expects the youngster to begin the season at Triple-A Las Vegas. (
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PORT ST. LUCIE — Zack Wheeler’s goal of making the Mets’ decision on him a difficult one this spring is off to a terrific start.

The fireballing phenom had early jitters yesterday, but pitched two scoreless innings in the Mets’ 5-3 victory over the Nationals to open the Grapefruit League season.

Stephen Strasburg brought star appeal to the game — and promptly allowed a two-run homer to Ruben Tejada in the first inning — but the 22-year-old Wheeler certainly has the tools to potentially approach the Nationals ace.

The reassuring Wheeler needed came from his teammates after he walked the first batter he faced, Steve Lombardozzi, and fired a pitch off catcher John Buck’s mitt that was ruled a passed ball.

Buck and David Wright then led the procession to the mound to calm the rookie.

“They were like, ‘Just settle down — they can’t hit you,’ ” said Wheeler, who had faced Buck, Marlon Byrd and Justin Turner in live batting practice earlier this week to give the Mets their first glimpse of the righty. “They all saw me the other day, so they were like, ‘We saw what you did the other day, just go after them, go pitch.’ ”

“I asked him, ‘Are you a little amped up? Is your heart beating?’ ” Buck said. “And he kind of chuckled and said, ‘Yeah, just a little.’ I was like, ‘You should be.’ It was kind of funny — he was shocked I asked in the middle of an intense moment.”

Wheeler retired Bryce Harper and then struck out Tyler Moore and Chad Tracy — on 96 and 94 mph heat, respectively — to end the third inning. Wheeler had entered after Shaun Marcum allowed three runs over the first two innings.

In the fourth, Wheeler got two quick outs, allowed a single to Chris Snyder and retired Micah Owings.

Even with Johan Santana’s situation murky — the lefty has been scratched from his first scheduled spring start and won’t pitch until at least March 10 — Wheeler remains a long shot to make the team out of spring training as the Mets attempt to avoid the temptation of potentially rushing him to the big leagues. The Mets also want to avoid starting Wheeler’s arbitration clock a year early. They can delay the process by keeping him in the minors until late May.

“Is it etched in stone?” manager Terry Collins said about the decision to have Wheeler at Triple-A Las Vegas starting the season. “No, but it’s close.”

If Santana, who needs to build up strength in his shoulder, were deemed close as the season began, the Mets would likely choose among Jenrry Mejia, Jeremy Hefner and Collin McHugh for that spot, according to a club official. But Wheeler could be more of a consideration if Santana or another starter were to suffer a long-term setback.

Nevertheless, Santana still has every intention of taking the ball for Opening Day on April 1 at Citi Field.

“I’ll be ready,” Santana told The Post. “I’ll take my time. I’ve been doing it a few years. I know what I am doing.”

The Mets would like to get Santana four exhibition starts, gradually building him up to 90-to-95 pitches, but pitching coach Dan Warthen said it’s too early to determine when the lefty would pitch. Collins became concerned with Santana’s lack of arm speed during a bullpen session on Wednesday and later decided to scrap his scheduled March 2 start against the Marlins.

In the meantime, the Mets will continue to watch Wheeler and dream about the future.

“He’s what I’ve been told about him, obviously great arm, and I’m really impressed with his breaking ball,” Collins said. “I know his first inning he was all geeked up and settled down, and the second inning he pounded the strike zone, which was pretty impressive to see.”